Problems with Meypro guar gum for thickening acid dyes

Name: Marjory

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Country or region: Canada

Message: I have been painting with thickened acid (usually Aljo) dyes for years. I use Meypro gum as the thickening agent. In the summer one large batch of Meypro gum went moldy and had to be thrown out. Some, but not all, of the thickened dyes we've made up recently are becoming thin within a week and sometimes the colours are separating. The Meypro gum I'm using is all from the same source but ordered at intervals over the past ten months. The recipe used and mixing process hasn't changed. Any ideas about why this is happening? I appreciate your help.

Meypro gum is a brand of guar gum, made from guar beans. Like all of the different dye thickeners, guar gum is a polysaccharide, a long chain of sugars, in this case including galactose and mannose. It's used not only for thickening acid dyes, but also for thickening the caustic paste used to burn out devoré patterns on mixed fiber fabrics. It's not used for reactive dyes because it reacts with those dyes.

You're still buying your Meypro from the same source as always before, but the people you buy it from may have had to switch suppliers, or their suppliers may be having problems. It's obvious that there's something very different about the product you're getting now.

I haven't heard of guar gum supply problems until now, but it sounds surprisingly like the problems people have been having lately with alginate, a seaweed-based thickener used more often for reactive dyes, although the two types of thickeners are completely different both in the plants they originate from and the identity of the chemicals responsible for their thickener properties.

The dye supply retailer Dharma Trading Company wrote, "we have just gotten over a world wide shortage of Alginate Kelp. But the brand we used to carry is no longer available anywhere. The product we now have to carry is different from the old kind, particularly the HV, slightly finer, lighter in color, and you may have to use a little more, depending on your use. We will be doing some experiments, and will post on this page if we find any radical difference. But this is it, the only one that anyone can get any more."

Meanwhile, they're also having problems, more serious ones, with the main competitor for thickening reactive dyes, a product with the brand name Superclear, a poly(acrylic acid)-based thickener: "Attention - we can no longer get this product. We bought the last of it and the manufacturer can no longer get the ingredients. They have sent us samples of several alternatives, but they have been completely unacceptable. the last one wasn't even safe to use. We are trying to get you a substitute, but we are only going to accept one if it works and is relatively safe. For now, Sodium Alginate powdered thickener is your best bet for now."

It seems very odd that three completely different dye thickeners should have supply problems at almost the same time.

The first thing you should do is call your current supplier for Meypro gum, and ask whether they can tell you anything about the quality problems you've been experiencing. It's unlikely that you're the only one to have experienced this. Perhaps they can supply a higher grade that acts more like the old product. It might be easier to get them to supply you with a higher-quality product, if one is even available, than to find other sources and test each of them for suitability for your needs.

To fight the more rapid breakdown of the guar gum, perhaps you could try refrigeration, if you haven't been doing that already. Be sure to return your gum mixture completely to room temperature before you attempt to use it, and check to make sure that cold temperatures don't have a hard-to-reverse effect on the thickener; it's extremely important to test this, since, for example, liquids thickened with starch are never the same after refrigeration as they were before. If you want to try using a preservative to stop the growth of mold, I've seen a recipe (in J. N. Liles book, "The Art and Craft of Natural Dyeing") that calls for adding 0.1% sodium benzoate, or about one teaspoon per gallon.

Now that the shortage of alginate is over, it's another alternative for you to use in thickening your acid dyes. Canadian suppliers for sodium alginate that is suitable for dyeing including G&S Dye in Toronto, Harmony Hand Dyes in Tisdale, Saskatchewan, and Maiwa Handprints in Vancouver. Maiwa also sells guar gum; if they are not your current supplier, perhaps they would be a good alternative source. Maiwa is a reputable supplier; in your situation, I might try their guar gum first.

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Posted: Friday - February 03, 2012 at 10:00 AM

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Problems with Meypro guar gum for thickening acid dyes

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